Poland is remembering the momentous events of 25 years ago, when Solidarity was born - the only mass independent political movement to emerge inside the Soviet bloc.

The Gdansk Agreement between the Communist authorities and striking workers was signed on 31 August 1980 - and nine years later a wave of protest across eastern Europe demolished the Soviet bloc.

The BBC's world affairs correspondent Mike Donkin asked the former Solidarity leader Lech Walesa about the revolutionary changes that shook Poland in 1980.

As you scaled the walls of the Gdansk shipyard here 25 years ago to start the strike what was on your mind?

It was yet another fight with communism - another contest with the system and this time I had to see how far I could go.

There had been many protests before. What made you think this time things could be different?

In the first instance I was well prepared and decisive. And at the same time I could see that the communist system had proved it was not able to compete with the western world, and in these conditions it was not in a fit state to survive to the 21st Century.

This was a battle for the rights of Polish people, not only for the workers of the shipyard. What rights were you fighting for?

Walesa rallied the strikers and won official recognition of Solidarity

In most cases people saw the fight in terms of living conditions. Our demands changed over the course of events.

In the first three days the demands were only for shipyard workers, and when these were met the strike was, in effect, over. But then because of pressure from other workplaces all over the country the strike was reborn, and became Solidarity. It became a national movement with different demands, including political ones.

For forty years after World War II, when this system was imposed on us, we had been fighting. We were unable to get rid of the system imposed on us as the war ended. The people were resigned and put the fight for freedom off for a later day.

And then something happened which was unprecedented in human history. A Pole became the Pope. A year after his election he arrived in Poland and the whole world was asking itself: How is this possible? The Pope visiting a communist nation.

The government in the end gave in quite quickly to Solidarity's demands. Why do you think they did that?

Oh no, it was not so quickly - it took nearly two weeks. And the government was forced to back down because the whole country was at a standstill.

Let me ask you about the fears of many Polish people. There were fears that you might win at the negotiating table but that would not be the end.

There were 200,000 Russian troops based permanently in Poland and a million more on our borders. And they had weapons of mass destruction as well. We knew all about that. But we were determined not to go back to work. They could kill us but they could not defeat us. They could us disperse us but they could not force us to work. So in fact the Communists did not have very effective weapons to use.

When the moment of victory came how did you feel?

When we were approaching the end of our battle I stood up and said 'You're all happy but I'm worried and frightened of what lies ahead of us'. Those who were carrying me on their shoulders then could soon be throwing stones at me.

So in a way the difficult part started after 31 August?

You've got to understand. It was clear to us that following this way would eventually lead to the collapse of Communism, the Warsaw Pact would cease to exist, but the whole pleasure of that would be at the expense of our economy, our cooperation, and our markets.

So how much was it the action of Solidarity which eventually brought down the Berlin Wall?

It did more than anything else that happened anywhere in the world. The further history moves on, the clearer it becomes how important that moment was.

The European Union couldn't have expanded, the unification of Germany would not have been possible. And other countries wouldn't have got their freedom if the Poles had not broken the Soviet bear's teeth. When other countries did their own thing, the bear could no longer bite.

General Wojciech Jaruzelski imposed martial law in 1981

Are you happy with the Poland that you and Solidarity helped to bring about - the Poland of today?

If someone told me 25 years ago that I would be having this interview with you, that I would be in a free country, in the European Union and in Nato, I wouldn't have believed them. If if they had put a gun to my head and said that IS going to be the case - well then, despite the gun, I would have been the happiest person in this galaxy.

But when I look back down the road I've seen Poland squander many opportunities since. And that makes me sad.

Also - we gave the West a great prize. It no longer needs its Cold War weapons. It's gained new markets in all the former communist states. But the fact that there are now so few jobs HERE doesn't seem to matter to the West.

As your fellow Poles celebrate this week, will you be celebrating with them, and what will you be thinking?

Of course I cannot BUT celebrate. I was leading the strike. And we were battling against the odds in pretty undemocratic times. So yes I will - I could hardly not celebrate the anniversary of this special moment in history.